Description (Adapted from Application): A large proportion of a variety of gastric disorders occurring in the industrialized countries have been attributed to infections by Helicobacter pylori. However, some patients suffering these symptoms are culture negative and antibody negative for H. pylori, and these disorders are often attributed to other causes, such as the habitual use of certain drugs. There have been reports of uncharacterized coccoid organisms proposed as the causative agent for gastric inflammation in some patients, and coccoid forms have been detected in gastric biopsy samples. Experimental proof of a role of the coccoid forms in the transmission of infection has not been possible because the coccoid forms could not be cultivated in the laboratory. A coccoid organism was recently cultivated from biopsy material obtained from patients suffering gram gastritis. The prototype isolate, designated strain SL-100, infects the porcine gastric antrum and binds to porcine gastric mucin in vitro. These observations suggest that the coccoid organisms isolated from these gastric patients may be human pathogens. Major goals of the proposed research are to (1) further characterize strain SL-100 and related isolated, and (2) determine the incidence, in this country and abroad, of infection or disease due to this species. The PI will test serum samples from normal and infected individuals to test for antibodies specific for this organism. He currently has clinical collaborators in the New York area, and the initial goal will be to attempt to cultivate the organism from biopsy material and to determine if antibodies directed against specific microbial proteins are correlated with infection or disease.